Gemcitabine, Docetaxel, Capecitabine, Cisplatin, Irinotecan as First-line Treatment for Metastatic Pancreatic Cancer

Purpose: Treatment of advanced pancreatic cancer with a single therapeutic at a maximal dose has been largely ineffective at increasing survival. Combination therapies are commonly studied but often limited by toxicity. We previously showed that low-dose multiagent therapy with gemcitabine, docetaxel (taxotere), capecitabine (xeloda), and cisplatin (GTX-C) was safe, well tolerated, and effective (NCT01459614). Here, we hypothesize that adding irinotecan to GTX-C may improve survival with minimal toxicity. Experimental Design: Patients with treatment-naïve metastatic pancreatic adenocarcinoma were treated with gemcitabine, docetaxel (taxotere), capecitabine (xeloda), cisplatin, and irinotecan (GTX-CI). Treatment consisted of capecitabine 500mg twice daily on days 1-14 and gemcitabine 300 to 500 mg/m2, docetaxel 20mg/m2, cisplatin 15 to 20mg/m2, and irinotecan20 to60mg/m2 on days 4 and 11 of a 21-day cycle. The primary objective was 9-month overall survival (OS). Secondary objectives included response rate (RR), disease control rate (DCR), progression-free survival (PFS), and OS. Results: The regimen was well tolerated. The recommended phase II dose was gemcitabine 500 mg/m2, docetaxel 20 mg/m2, capecitabine 500 mg po bid, cisplatin 20 mg/m2, and irinotecan 20 mg/m2. Median follow-up in phase II was 11.02 months (2.37-45.17). Nine-month OS rate was 57% [95% confidence interval (CI): (41-77)]. RR was 57% [95% CI: (37-75) 50% PR and 7% CR]. DCR was 87% [95% CI: (69-96)].Median OS and PFS were 11.02 [95% CI: (8.54-21.09)] and 8.34 [95% CI: (6.34-NA)] months, respectively. Conclusions: The addition of irinotecan to GTX-C was safe and well tolerated. While the study did not meet its primary objective, the responses were clinically meaningful using a well-tolerated regimen. Significance:We aimed to optimize the previously reported efficacious regimen of low-dose multiagent therapy with GTX-C for the treatment of metastatic pancreatic ductal adenocarcinoma by adding irinotecan. The primary objective was not met, but GTX-CI was well tolerated. The RR of 57%, median PFS of 8.3 months, median OS of 11 months, and 36-month OS rate of 19%suggest clinical benefit. Further optimization of this regimen is warranted.